Optimizing turbine cycle heat rate against cooling tower operations

A cooling tower interacts with the turbine cycle through heat rejection to the circulating water at the condenser. Thereby the turbine back-pressure is reduced which improves turbine efficiency. The colder the re-cooled water temperature, the lower the back-pressure, the lower the turbine cycle heat rate. However, the ambient wet bulb temperature, cold water temperature, condenser back-pressure and turbine cycle heat rate do not interact linearly. That sets the stage for an optimization exercise to minimize fuel costs or to maximize net saleable power.